The present invention relates to a melamine resin foam. More particularly, the present invention relates to a melamine resin foam with excellent oil repellency, which is improved in oil repellency and consequently can be suitably used as a sound-insulating material or a heat-insulating material for various applications, particularly those where the foam is exposed to oil over a long period of time.
As well known, melamine-formaldehyde resins are a thermosetting resin and an amino resin, obtained by the reaction of melamine with formaldehyde, and those of high molecular weight are in use as heat-resistant tableware, surface plate of table, etc. for their excellent heat resistance.
It is also known that melamine-formaldehyde resin foams exhibit excellent flame retardancy as compared with other organic resin foams and further have excellent sound-insulating property and heat-insulating property. Therefore, use of melamine resin foams as a construction material, or as a sound- and heat-insulating material in automobiles, industrial machinery, factories, etc. is expected.
Melamine resin foams, however, have various problems. That is, they are very fragile and the fragility is striking when they have a high expansion ratio; having very high water absorbability, they show property deterioration due to moisture absorption and adverse effects to the surrounding members when used as a construction material, a sound-insulating material, etc.; when used for industrial applications as a heat insulating material or the like, they may invite substantial reduction in flame retardancy due to oil absorption. Thus, melamine resin foams have had limited applications.
In order to alleviate the above-mentioned problems of melamine resin foams, of property deterioration due to moisture absorption and adverse effects to the surrounding members, there was proposed, in JP-A-7-26054, a method of endowing a melamine resin foam with water repellency using a silicone resin. However, no melamine resin foam endowed with oil repellency has been provided heretofore.
The object of the present invention is to alleviate the above-mentioned problems of the prior art and provide a melamine resin foam endowed with excellent oil repellency and which is improved in fragility without deteriorating the superior properties (e.g. sound-insulating property) inherently possessed by melamine resin foams.
Disclosure of the Invention
According to the present invention, there is provided a melamine resin foam with excellent oil repellency, obtained by coating an oleophobic component on a base material produced by foaming a resin composition comprising, as the main components, a melamine-formaldehyde condensate and a foaming agent.
The present inventors made a study with an idea that when a melamine resin foam is coated with an oleophobic component, the melamine resin foam may be endowed with oil repellency and moreover may be improved in fragility when a load is applied thereto, because the coated oleophobic component may disperse the load and may reduce the destruction of the skeleton of the foam. As a result, the present invention has been completed.
Best Mode for Carrying Out the Invention